1. Field of the Invention
The present invention relates to an inorganic article for containing or contacting a solution for crystal growth of a compound semiconductor and a liquid-phase epitaxy apparatus using the same.
2. Description of the Prior Art
There are various types of inorganic devices used for the crystal growth of a compound semiconductor, including a carbon boat (a graphite boat), a container (a crucible), and a lid of the container, which are commonly made of graphite and employed where airtightness is required.
For example, the carbon boat is generally used in a slide boat procedure employed for liquid-phase epitaxy method of the epitaxial growth technology.
In operation of the liquid phase epitaxy, a solution for epitaxial growth is heated to a high temperature (of 700.degree. to 900.degree. C.) and then, cooled down. The solution contains diffusive elements having a high vapor pressure, such as arsenic, phosphorus, and the like and also, the carbon boat must be used in an airtight situation. However, the graphite is generally porous and the carbon boat made of the graphite has a large number of tiny pores on the surface thereof and, thus is unsatisfactory in the airtightness.
As a result, such diffusive elements tend to be dispersed through the tiny pores to the outside of the boat, whereby the stoichiometric composition of the solution will be destroyed causing structural defects of crystals. This disadvantage will become more serious during a longer period of the crystal growth.
The above-mentioned problems related to porousness also apply to porous inorganic structures in general, such as vessels made from graphite or ceramic (e.g. h-BN, Al.sub.2 O.sub.3, etc.) exemplified by a crucible, lid of vessels and so on.